Method of manufacturing semiconductor device and substrate processing apparatus

ABSTRACT

A manufacturing method of a semiconductor device of the present invention includes the step of forming an insulating film on a substrate, and the step of forming a high dielectric constant insulating film on the insulating film, and the step of forming a titanium aluminium nitride film on the high dielectric constant insulating film, wherein in the step of forming the titanium aluminum nitride film, formation of an aluminium nitride film and formation of a titanium nitride film are alternately repeated, and at that time, the aluminium nitride film is formed firstly and/or lastly.

BACKGROUND

1. Technical Field

The present invention relates to a manufacturing method of asemiconductor device and a substrate processing apparatus, andparticularly relates to the manufacturing method of the semiconductordevice including the step of forming a metal film on a substrate and thesubstrate processing apparatus for forming the metal film on thesubstrate.

2. Description of Related Art

In a Metal/High-k gate stack, when high-temperature heat treatment isapplied, there is a problem that an effective work function of a metalgate electrode is shifted to midgap, due to Fermi-level pinningphenomenon. This phenomenon appears remarkably in p-MOSFET inparticular. As a method of avoiding this phenomenon, research of using ametal composite film, such as a Metal-Al—N film, in the gate electrode,has been recently conducted. A TiAlN film and a RuAlN film are given asexamples of the Metal-Al—N film.

As a conventional film-forming method of the metal composite film, anALD method can be given as a main stream, wherein two precursors andreactive gas are alternately supplied (for example see non-patentdocuments 1 and 2). The non-patent documents 1 and 2 disclose an exampleof forming a film by PEALD (Plasma Enhanced ALD) method using plasma.

(Related Technical Document) (Non-Patent Document) (Non-PatentDocument 1) Young Ju Lee and Sang-Won Kang:Electrochemical andSolid-State Letters, 6(5) C70-C72 (2003) “Ti—Al—N Thin Films Prepared bythe Combination of Metallorganic Plasma-Enhanced Atomic Layer Depositionof Al and TiN”

(Non-patent document 2)Youn Ju Lee and Sang-Won Kang: J. Vac. Sci. Technol. A, Vol. 21, No. 5,September/October 2003 “Controlling the composition of Til-XAIXN thinfilms by modifying the number of TiN and AlN subcycles in atomic layerdeposition”

SUMMARY OF THE INVENTION

However, when the metal composite film is formed by ALD method, there isa problem that residual impurities resulting from the precursor can notbe completely removed, due to its low processing temperature. Meanwhile,the metal composite film is also formed by PEALD method using plasma asshown in the non-patent document 1, However, when a film is formed byPALD method, flatness of the film is sometimes deteriorated, and whenthis method is applied to formation of the gate electrode, becauseplasma is used, there is a risk of plasma damage added to a gateinsulating film and increase of EOT.

Also, when the metal composite film is formed by ALD method by alternatesupply of two kinds of precursors and reactive gas, its film-formingrate is problematic, thus involving a great problem that tremendous timeis required and the precursor is wasted.

Therefore, it is desirable to provide a manufacturing method of asemiconductor device and a substrate processing apparatus capable ofreducing residual impurities in the film without adding plasma damagethereto, capable of improving flatness of the film, and further capableof improving the film-forming rate while suppressing a use amount ofprecursor.

According to one aspect of the present invention, there is provided amanufacturing method of a semiconductor device, including the steps of:

forming an insulating film on a substrate;

forming a high dielectric constant insulating film on the insulatingfilm; and

forming a titanium aluminium nitride film on the high dielectricconstant insulating film,

wherein in the step of forming the titanium aluminium nitride film,formation of an aluminium nitride film and formation of a titaniumnitride film are alternately performed repeatedly, and at that time, thealuminium nitride film is formed firstly and/or lastly. Here, the highdielectric constant insulating film means the insulating film having ahigher dielectric constant than the dielectric constant of SiO₂ (about4). Also, forming the aluminium nitride film firstly and/or lastly meansthe forming the aluminium nitride film firstly (AlN-first), forming thealuminium nitride film lastly (AlN-last), or the forming the aluminiumnitride film firstly and lastly (AlN first and last).

According to another aspect of the present invention, there is provideda manufacturing method of a semiconductor device, including the stepsof:

forming an insulating film on a substrate;

forming a high dielectric constant insulating film on the insulatingfilm; and

forming a titanium aluminium nitride film on the high dielectricconstant insulating film,

wherein in the step of forming the titanium aluminium nitride film,formation of an aluminium nitride film by ALD method and formation of atitanium nitride film by CVD method are alternately performedrepeatedly, in the same processing chamber, with purge of an inside ofthe processing chamber sandwiched between them, in a state of settingtemperature of the substrate to be the same temperature, and at thattime, the aluminium nitride film is formed firstly and/or lastly.

According to further another aspect of the present invention, there isprovided a substrate processing apparatus, including:

a processing chamber that processes a substrate on which a highdielectric constant insulating film is formed on the surface through aninsulating film;

a first source supply system that supplies a first source containingaluminium atoms into the processing chamber;

a second source supply system that supplies a second source containingtitanium atoms into the processing chamber;

a reactive gas supply system that supplies reactive gas containingnitrogen atoms into the processing chamber;

a heater that heats the substrate in the processing chamber; and

a controller that controls the first source supply system, the secondsource supply system, the reactive gas supply system, and the heater, sothat a titanium aluminium nitride film is formed on the high dielectricconstant insulating film formed on the substrate, by alternately andrepeatedly performing formation of an aluminium nitride film bysupplying the first source and the reactive gas into the processingchamber and formation of a titanium nitride film by supplying the secondsource and the reactive gas into the processing chamber, and at thattime, the aluminium nitride film is formed firstly and/or lastly.

According to the manufacturing method of a semiconductor device and thesubstrate processing apparatus of the present invention, residualimpurities in a film can be reduced with no plasma damage added thereto,then flatness of the film can be improved, and further a film-formingrate can be improved while suppressing a use amount of a precursor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a film formation sequence view in the substrate processingstep according to an embodiment of the present invention.

FIG. 2 is a block diagram of a gas supply system possessed by asubstrate processing apparatus according to an embodiment of the presentinvention.

FIG. 3 is a sectional block diagram of the substrate processingapparatus at the time of processing a wafer according to an embodimentof the present invention.

FIG. 4 is a sectional block diagram of the substrate processingapparatus at the time of transferring a wafer according to an embodimentof the present invention.

FIG. 5 is a flowchart of the substrate processing steps according to anembodiment of the present invention.

FIG. 6 is a view showing an evaluation result of an example 1, whereinFIG. 6A shows TDMAT supply time dependency of the CVD-TiN film thicknesson HfSiON, AlN, SiO₂ in CVD-TiN film formation, and FIG. 6B shows ALDcycle number dependency of the ALD-AlN film thickness on HfSiON, TiN,SiO₂ in ALD-AlN film formation.

FIG. 7 is a view showing an evaluation result of an example 2, whereinFIG. 7A shows each sectional TEM photograph after ALD-AlN film formationand CVD-TiN film formation are repeatedly performed and laminate filmscomposed of 5-layers, 11-layers, and 21-layers are formed, and FIG. 7Bshows each sectional TEM photograph after ALD-AlN film formation andCVD-TiN film formation are repeatedly performed, then laminated filmscomposed of 5-layers, 11-layers, and 21-layers are formed, and N₂annealing is applied thereto at 900° C.

FIG. 8 is a view showing an evaluation result of an example 3, whereinFIG. 8A shows an XPS depth direction profile after a laminate filmcomposed of 11 layers is formed and N₂ annealing is applied thereto at900° C., and FIG. 8B shows the XPS depth direction profile after alaminate film composed of 21 layers is formed and N₂ annealing isapplied thereto at 900° C.

FIG. 9 is a view showing an evaluation result of an example 4, whereinFIG. 9A is a view showing ALD-AlN cycle number dependency of Al/Ticoncentration in the TiAlN film, and FIG. 9B is a view showing Alconcentration dependency of resistivity.

FIG. 10 is a view showing an evaluation result of an example 5, whereinFIG. 10A shows an SEM photograph after the TiAlN film is formed byrepeating CVD-TiN film formation and ALD-AlN film formation, and N₂annealing is applied thereto at 900° C. and FIG. 10B shows a sectionalTEM photograph after the TiAlN film is formed by repeating the CVD-TiNfilm formation and ALD-AlN film formation, and N₂ annealing is appliedthereto at 900° C., and FIG. 10C shows an AFM photograph after the TiAlNfilm is formed by repeating the CVD-TiN film formation and the ALD-AlNfilm formation and N₂ annealing is applied thereto at 900° C.

FIG. 11 is a view showing an evaluation result of an example 6, whereinFIG. 11A shows a gate structure (evaluation sample structure) ofp-MOSFET wherein the TiAlN film formed by repeating the CVD-TiN filmformation and ALD-AlN film formation is applied to a gate electrode, andFIG. 11B shows a condition and a lamination structure when the TiAlNfilm is formed by repeating the CVD-TiN film formation and the ALD-AlNfilm formation, and FIG. 11C is a view showing Al concentrationdependency of effective work function in the TiAlN film.

FIG. 12 is a view showing an evaluation result of an example 7, whereinFIG. 12A shows the gate structure (evaluation sample structure) ofp-MOSFET wherein the TiAlN film formed by repeating the CVD-TiN filmformation and the ALD-AlN film formation is applied to the gateelectrode, and FIGS. 7B and 7C show the condition and the laminationstructure when the TiAlN film is formed by repeating the CVD-TiN filmformation and the ALD-AlN film formation, and FIG. 12D is a view showingAl concentration dependency of the effective work function in the TiAlNfilm.

FIG. 13 is a view showing an evaluation result of an example 7, whereinFIG. 7A shows the gate structure (evaluation sample structure) ofp-MOSFET wherein the TiAlN film formed by repeating the CVD-TiN filmformation and the ALD-AlN film formation is applied to the gateelectrode, and FIGS. 13B and 13C show the condition and the laminationstructure when the TiAlN film is formed by repeating the CVD-TiN filmformation and the ALD-AlN film formation, and FIG. 7D is a view showingAl concentration dependency of the effective work function in the TiAlNfilm.

FIG. 14A is a view showing a variation of degree of oxidation of theTiAlN film with elapse of time, with CVD-TiN film set as an uppermostlayer, and FIG. 14B is a view showing the variation of the TiAlN filmwith elapse of time, with ALD-AlN film set as an uppermost layer.

FIG. 15 is a schematic block diagram of a vertical processing furnace ofa vertical ALD apparatus suitably used in this embodiment, wherein FIG.15A shows a vertical sectional face of a processing furnace part 302,and FIG. 15B shows a sectional view of the processing furnace 302 parttaken along the line A-A in the FIG. 15A.

FIG. 16 is a film formation sequence in the substrate processing stepaccording to further another embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION (1) Structure ofthe Substrate Processing Apparatus

First, the structure of the substrate processing apparatus according tothis embodiment will be described, with reference to FIG. 3 and FIG. 4.FIG. 3 is a sectional block diagram of the substrate processingapparatus at the time of processing a wafer according to an embodimentof the present invention, and FIG. 4 is a sectional block diagram of thesubstrate processing apparatus at the time of transferring a waferaccording to an embodiment of the present invention.

(Processing Chamber)

As shown in FIG. 3 and FIG. 4, the substrate processing apparatusaccording to this embodiment includes a processing container 202. Theprocessing container 202 is constituted as a flat air-tightly sealedcontainer, with a lateral sectional face formed into a circular shape.Further, the processing container 202 is made of metal materials such asaluminium (Al) and stainless (SUS). A processing chamber 201 forprocessing a wafer 200 such as silicon wafer as a substrate is formed inthe processing container 202.

A support table 203 for supporting the wafer 200 is provided in theprocessing chamber 201. A susceptor 217, being a support plate made of,for example, quartz (SiO₂), carbon, ceramics, and silicon carbide (SiC),aluminium oxide (Al₂O₃), or aluminium nitride (AlN) is provided on anupper surface of the support table 203 in direct contact with the wafer200. Moreover, a heater 206, being a heating unit (heating source) forheating the wafer 200, is built in the support table 203. In addition, alower end portion of the support table 203 is passed through a bottompart of the processing container 202.

An elevation mechanism 207 b for elevating the support table 203 isprovided outside of the processing chamber 201. By elevating the supporttable 203 by actuating this elevation mechanism 207 b, the wafer 200supported on the susceptor 217 can be elevated. The support table 203 islowered to a position (wafer transfer position) shown in FIG. 4 at thetime of transferring the wafer 200, and is elevated to a position (waferprocessing position) shown in FIG. 3 at the time of processing the wafer200. In addition, periphery of the lower end portion of the supporttable 203 is covered with a bellows 203 a, and an inside of theprocessing chamber 201 is air-tightly maintained.

Further, for example, three lift pins 208 b are provided on the bottomsurface (floor surface) of the processing chamber 201 in such a manneras being upright in a vertical direction. In addition, on the supporttable 203 (including susceptor 217), through holes 208 a, through whichsuch lift pins 208 b are passed through, are provided at positionscorresponding to the lift pins 208 b respectively. Then, when thesupport table 203 is lowered to the wafer transfer position, as shown inFIG. 4, upper end portions of the lift pins 208 b are protruded from anupper surface of the susceptor 217, thus supporting the wafer 200 frombelow by the lift pins 208 b. Further, when the support table 203 iselevated to the wafer processing position, as shown in FIG. 3, the liftpins 208 b are embedded from the upper surface of the susceptor 217, sothat the wafer 200 is supported by the susceptor 217 from below. Notethat the lift pins 208 b are desirably made of, for example, materialssuch as quartz and alumina, because the lift pins 208 b are directlybrought into contact with the wafer 200.

(Wafer Transfer Port)

A wafer transfer port 250 for transferring the wafer 200 toinside/outside of the processing chamber 201 is provided on the innerwall side of the processing chamber 201 (processing container 202). Agate valve 251 is provided in the wafer transfer port 250, and byopening the gate valve 251, the inside of the processing chamber 201 andthe inside of the transfer chamber (preliminary chamber) 271 arecommunicated with each other. The transfer chamber 271 is formed in thetransfer container (air-tightly sealed container) 272, and a transferrobot 273 for transferring the wafer 200 is provided in the transferchamber 271. A transfer arm 273 a for supporting the wafer 200 at thetime of transferring the wafer 200 is provided in the transfer robot273. By opening the gate valve 251, with the support table 203 loweredto the wafer transfer position, the wafer 200 can be transferred betweenthe inside of the processing chamber 201 and the inside of the transferchamber 271 by the transfer robot 273. The wafer 200 transferred intothe processing chamber 201 is temporarily placed on the lift pins 208 bas described above. In addition, a load-lock chamber not shown isprovided on the opposite side to the side where the wafer transfer port250 of the transfer chamber 271 is provided, so that the wafer 200 canbe transferred between the inside of the load-lock chamber and theinside of the transfer chamber 271 by the transfer robot 273. Note thatthe load-lock chamber functions as a preliminary chamber for temporarilyhousing unprocessed or already processed wafer 200.

(Exhaust System)

An exhaust port 260 for exhausting an atmosphere in the processingchamber 201 is provided on inner wall side of the processing chamber 201(processing container 202) and on the opposite side of the wafertransfer port 250. An exhaust tube 261 is connected to the exhaust port260 through an exhaust chamber 260 a, and a pressure adjuster 262 suchas an APC (Auto Pressure Controller) for controlling a pressure in theprocessing chamber 201 to be a prescribed pressure, a source recoverytrap 263, and a vacuum pump 264 are sequentially connected to theexhaust tube 261 in series. An exhaust system (exhaust line) is mainlyconstituted of the exhaust port 260, the exhaust chamber 260 a, theexhaust tube 261, the pressure adjuster 262, the source recovery trap263, and the vacuum pump 264.

(Gas Inlet Port)

A gas inlet port 210 for supplying each kind of gas into the processingchamber 201 is provided on an upper surface (ceiling wall) of a showerhead 240 as will be described later provided in an upper part of theprocessing chamber 201. Note that the structure of the gas supply systemconnected to the gas inlet port 210 will be described later.

(Shower Head)

The shower head 240, being a gas dispersion mechanism, is providedbetween the gas inlet port 210 and the processing chamber 201. Theshower head 240 includes a dispersion plate 240 a for dispersing the gasintroduced from the gas inlet port 210, and a shower plate 240 b forfurther uniformly dispersing the gas passed through the dispersion plate240 a and supplying the gas to the surface of the wafer 200 on thesupport table 203. A plurality of ventilation holes are provided on thedispersion plate 240 a and the shower plate 240 b. The dispersion plate240 a is disposed so as to oppose to an upper surface of the shower head240 and the shower plate 240 b, and the shower plate 240 b is disposedso as to oppose to the wafer 200 on the support table 203. In addition,space is provided between the upper surface of the shower head 240 andthe dispersion plate 240 a, and between the dispersion plate 240 a andthe shower plate 240 b respectively, and such a space functionsrespectively as a first buffer space (dispersion chamber) 240 c fordispersing the gas supplied from the gas inlet port 210, and a secondbuffer space 240 d for dispersing the gas passed through the dispersionplate 240 a.

(Exhaust Duct)

A step part 201 a is provided on the inner wall side of the processingchamber 201 (processing container 202). Then, this step part 201 a isconstituted so that a conductance plate 204 is held in the vicinity ofthe wafer processing position. The conductance plate 204 is constitutedas a donut-shaped (ring-shaped) disc, with a hole formed therein forhousing the wafer 200 in an inner peripheral part. A plurality ofdischarge ports 204 a arranged in a peripheral direction at prescribedintervals are provided on an outer peripheral part of the conductanceplate 204. The discharge port 204 a is discontinuously formed, so thatthe inner peripheral part of the conductance plate 204 can be supportedby the outer peripheral part of the conductance plate 204.

Meanwhile, a lower plate 205 is mounted on the outer peripheral part ofthe support table 203. The lower plate 205 includes a ring-shaped recesspart 205 b and a flange part 205 a integrally provided in the insideupper part of the recess part 205 b. The recess part 205 b is providedso as to cover the gap between the outer peripheral part of the supporttable 203 and the inner wall side of the processing chamber 201. A plateexhaust port 205 c for discharging (flowing) the gas to the side of theexhaust port 260 from the inside of the recess part 205 b, is providedat a part in the vicinity of the exhaust port 260 on the bottom part ofthe recess part 205 b. The flange part 205 a functions as an engagingmember to be mounted on an upper outer peripheral edge of the supporttable 203. By making the flange part 205 a mounted on the upper outerperipheral edge of the support table 203, the lower plate 205 iselevated and lowered together with the support table 203, in associationwith an elevation and lowering of the support table 203.

When the support table 203 is elevated to the wafer processing position,the lower plate 205 is also elevated to the wafer processing position.As a result, the upper surface part of the recess part 205 b of thelower plate 205 is covered by the conductance plate 204 held in thevicinity of the wafer processing position, thus forming an exhaust duct259, with inside of the recess part 205 b as a gas flow passage area. Inaddition, at this time, the inside of the processing chamber 201 ispartitioned into a processing chamber upper part in an upper part of theexhaust duct 259, and a processing chamber lower part in a lower part ofthe discharge duct 259, by the exhaust duct 259 (the conductance plate204 and the lower plate 205) and the support table 203. Note that theconductance plate 204 and the lower plate 205 are preferably made of amaterial that can be held at a high temperature such as quartz for hightemperature resistance and high load resistance, in consideration of acase of etching reaction products deposited on an inner wall of theexhaust duct 250 (case of self-cleaning).

Here, flow of the gas in the processing chamber 201 in the waferprocessing will be described. First, the gas supplied to the upper partof the shower head 240 from the gas inlet port 210 enters into thesecond buffer space 240 d from a plurality of holes, through the firstbuffer space (dispersion chamber) 240 c, and further passes through aplurality of holes of the shower plate 240 b and supplied into theprocessing chamber 201, and uniformly supplied onto the wafer 200. Then,the gas supplied onto the wafer 200 radially flows toward outside of thewafer 200 in a diameter direction. Then, excess gas after brought intocontact with the wafer 200 radially flows toward the outside of thewafer 200 in the diameter direction, over the exhaust duct 259positioned on the outer peripheral part of the wafer 200, namely, overthe conductance plate 204, and is discharged into a gas flow passagearea (into the recess part 205 b) in the exhaust duct 259, from thedischarge port 204 a provided in the conductance plate 204. Thereafter,the gas flows through the exhaust duct 259, and is exhausted to theexhaust port 260 via the plate exhaust port 205 c. By flowing the gasthis way, a gas flow coming round to the rear side of the support table203 and the bottom side of the processing chamber 201 is suppressed.

<Gas Supply System>

Subsequently, the structure of the gas supply system connected to theaforementioned gas inlet port 210 will be described, with reference toFIG. 2. FIG. 2 is a block diagram of the gas supply system (gas supplyline) of the substrate processing apparatus according to thisembodiment.

The gas supply system of the substrate processing apparatus according tothis embodiment includes a bubbler, being a vaporization part forvaporizing liquid source in a liquid state at a normal temperature, asource gas supply system for supplying source gas obtained by vaporizingthe liquid source by the bubbler into the processing chamber 201; and areactive gas supply system for supplying reactive gas different from thesource gas into the processing chamber 201. Further, the substrateprocessing apparatus according to the embodiment of the presentinvention includes a purge gas supply system for supplying purge gasinto the processing chamber 201; and a vent (bypass) system forexhausting the source gas from the bubbler so as to bypass theprocessing chamber 201 without supplying this source gas into theprocessing chamber 201. The structure of each part will be describedbelow.

<Bubbler>

A first source container (first bubbler) 220 a for containing a firstsource (source A), being a liquid source, and a second source container(second bubbler) 220 b for supplying a second source (source B), beingthe liquid source, are provided outside of the processing chamber 201.The first bubbler 220 a and the second bubbler 220 b are constituted asa tank (air-tightly sealed container) capable of containing (filling)inside with the liquid source respectively, and are also constituted asthe vaporization part for generating the source gas by vaporizing theliquid source by bubbling. In addition, the first bubbler 220 a, thesecond bubbler 220 b, and a sub-heater 206 a for heating the liquidsource inside are provided around the first bubbler 220 a and the secondbubbler 220 b. As the first source, for example, TDMAT(Tetrakis-Dimethyl-Amido-Titanium), being an organic metal liquid sourcecontaining Ti (titanium) element is used, and as the second source, forexample, TMA (Trimethylaluminum), being the organic metal liquid sourcecontaining Al (aluminium) element is used.

A first carrier gas supply tube 237 a and a second carrier gas supplytube 237 b are respectively connected to the first bubbler 220 a and thesecond bubbler 220 b. A carrier gas supply source not shown is connectedto the upstream side end parts of the first carrier gas supply tube 237a and the second carrier gas supply tube 237 b. Also, the downstreamside end parts of the first carrier gas supply tube 237 a and the secondcarrier gas supply tube 237 b are immersed into the liquid sourcecontained in the first bubbler 220 a and the second bubbler 220 b,respectively. A mass flow controller (MFC) 222 a, being a flow ratecontroller for controlling a supply flow rate of the carrier gas andvalves va1 and va2 for controlling supply of the carrier gas, areprovided in the first carrier gas supply tube 237 a. A mass flowcontroller (MFC) 222 b, being the flow rate controller for controllingthe supply flow rate of the carrier gas, and valves vb1 and vb2 forcontrolling the supply of the carrier gas, are provided in the secondcarrier gas supply tube 237 b. Note that the gas not reactive with theliquid source is preferably used as the carrier gas, and for example,inert gas such as N₂ gas and Ar gas is suitably used. The first carriergas supply system and the second carrier gas supply system (firstcarrier gas supply line and second carrier gas supply line) arerespectively constituted mainly by the first carrier gas supply tube 237a, the second carrier gas supply tube 237 b, MFCs 222 a and 222 b, andvalves va1, va1, vb1, and vb2.

With above-described structure, by opening the valves va1, va2, vb1,vb2, and supplying the carrier gas, with flow rate controlled by theMFCs 222 a and 222 b from the first carrier gas supply tube 237 a andthe second carrier gas supply tube 237 b into the first bubbler 2201 andthe second bubbler 220 b, the liquid source contained in the firstbubbler 220 a and the second bubbler 220 b is vaporized by bubbling andthe source gas can be generated. Note that the supply flow rate of thesource gas can be determined from the supply flow rate of the carriergas. Namely, by controlling the supply flow rate of the carrier gas, thesupply flow rate of the source gas can be controlled.

<Source Gas Supply System>

A first source gas supply tube 213 a and a second source gas supply tube213 b for supplying the source gas generated in the first bubbler 220 aand the second bubbler 220 b into the processing chamber 201, arerespectively connected to the first bubbler 220 a and the second bubbler220 b. The upstream side end parts of the first source gas supply tube213 a and the second source gas supply tube 213 b are communicated witha space that exists in upper parts of the first bubbler 220 a and thesecond bubbler 220 b. The downstream side end parts of the first sourcegas supply tube 213 a and the second source gas supply tube 213 b aremerged with each other, which are then connected to the gas inlet port210 through a highly durable high speed gas valve V. The highly durablehigh speed gas valve V is a valve constituted so as to speedily switchsupply of the gas in a short time so that the gas can be exhausted. Inaddition, valves va3 and vb3 for controlling the supply of the sourcegas into the processing chamber 201, are respectively provided in thefirst source gas supply tube 213 a and the second source gas supply tube213 b.

With the above-described structure, the source gas can be generated byvaporizing the liquid source by the first bubbler 220 a and the secondbubbler 220 b, and by opening the valves va3 and vb3, the source gas canbe supplied into the processing chamber 201 from the first source gassupply tube 213 a and the second source gas supply tube 213 b. The firstsource gas supply system, the second source gas supply system (firstsource gas supply line and second source gas supply line) arerespectively constituted mainly by the first source gas supply tube 213a, the second source gas supply tube 213 b, the valves va3 and vb3, andthe highly durable high speed gas valve V.

Also, the first source supply system and the second source supply system(first source supply line and second source supply line) arerespectively constituted mainly by the first carrier gas supply system,the second carrier gas supply system, the first bubbler 220 a, thesecond bubbler 220 b, the first source gas supply system, and the secondsource gas supply system.

<Reactive Gas Supply System>

Further, a reactive gas supply source 220 c for supplying reactive gasis provided outside of the processing chamber 201. The upstream side endpart of the reactive gas supply tube 213 c is connected to the reactivegas supply source 220 c. The downstream side end part of the reactivegas supply tube 213 c is connected to the gas inlet port 210 through thehighly durable high speed gas valve V. A mass flow controller (MFC) 222c, being the flow rate controller for controlling the supply flow rateof the reactive gas, and valves vc1 and vc2 for controlling the supplyof the reactive gas, are provided in the reactive gas supply tube 213 c.For example ammonia (NH₃) is used as the reactive gas. The reactive gassupply system (reactive gas supply line) is constituted mainly by thereactive gas supply source 220 c, the reactive gas supply tube 213 c,the MFC 222 c, and the valves vc1 and vc2.

<Purge Gas Supply System>

A purge gas supply sources 220 d and 220 e for supplying purge gas, isprovided outside of the processing chamber 201. Upstream side end partsof the purge gas supply sources 220 d and 220 e are respectivelyconnected to the purge gas supply sources 220 d and 220 e. Downstreamside end parts of the purge gas supply tube 213 d are merged with thereactive gas supply tube 213 c, and are connected to the gas inlet port210 through the highly durable high speed gas valve V. Mass flowcontrollers (MFCs) 222 d and 222 e, being the flow rate controller forcontrolling the supply flow rate of the purge gas, and valves vd1, vd2,ve1, and ve2 for controlling the supply of the purge gas arerespectively provided in the purge gas supply tubes 213 d and 213 e. Forexample, the inert gas such as N₂ gas and Ar gas is used as the purgegas. The purge gas supply system (purge gas supply line) is constitutedmainly by the purge gas supply sources 220 d, 220 e, the purge gassupply tubes 213 d, 213 e, MFCs 222 d and 222 e, and the valves vd1,vd2, ve1, ve2.

<Vent (Bypass) System>

Further, the upstream side end parts of the first vent tube 215 a andthe second vent tube 215 b are respectively connected to the upstreamside of the valves va3 and vb3 of the first source gas supply tube 213 aand the second source gas supply tube 213 b. Also, the downstream sideend parts of the first vent tube 215 a and the second vent tube 215 bare merged with each other, and are connected to the upstream side ofthe source recovery trap 263, being the downstream side of the pressureadjuster 262 of the exhaust tube 261. Valves va4 and vb4 for controllingthe flow of the gas are respectively provided in the first vent tube 215a and the second vent tube 215 b.

With the above-described structure, by closing the valves va3 and vb3,and by opening the valves va4 and vb4, the gas flowing through the firstsource gas supply tube 213 a and the second source gas supply tube 213 bcan be bypassed the processing chamber 201 through the first vent tube215 a and the second vent tube 215 b without being supplied into theprocessing chamber 201, and can be exhausted respectively to outside ofthe processing chamber 201 from the exhaust tube 261. A first ventsystem and a second vent system (first vent line and second vent line)are respectively constituted mainly by the first vent tube 215 a, thesecond vent tube 215 b, and the valves va4 and vb4.

As described above, the sub-heater 206 a is provided around the firstbubbler 220 a and the second bubbler 220 b. However, other than thiscase, the sub-heater 206 a is also provided around the first carrier gassupply tube 237 a, the second carrier gas supply tube 237 b, the firstsource gas supply tube 213 a, the second source gas supply tube 213 b,the first vent tube 215 a, the second vent tube 215 b, the exhaust tube261, the processing container 202, and the shower head 240. Thesub-heater 206 a is constituted so as to prevent re-liquefication of thesource gas inside of these members, by heating these members, forexample, at a temperature of 100° C. or less.

<Controller>

In addition, the substrate processing apparatus according to thisembodiment has a controller 280 for controlling an operation of eachpart of the substrate processing apparatus. The controller 280 controlsoperations of the gate valve 251, the elevation mechanism 207 b, thetransfer robot 273, the heater 206, the sub-heater 206 a, the pressureadjuster (APC) 262, the vacuum pump 264, valves va1 to va4, vab1 to vb4,vc1 to vc2, vd1 to vd2, v31 to ve2, the highly durable high speed gasvalve V, the flow rate controllers 222 a, 222 b, 222 c, 222 d, and 222e.

(2) Substrate Processing Step

Subsequently, as one step of the manufacturing steps of thesemiconductor device according to the embodiment of the presentinvention, the substrate processing step of forming a thin film on thewafer by combining the CVD method and the ALD method, using theaforementioned substrate processing apparatus, will be described, withreference to FIG. 1 and FIG. 5. FIG. 5 is a flowchart of the substrateprocessing steps according to the embodiment of the present invention.Also, FIG. 1 is a film formation sequence view of the CVD step and theALD step in the substrate processing step according to the embodiment ofthe present invention. Note that in the description hereunder, theoperation of each part constituting the substrate processing apparatusis controlled by the controller 280.

Here, explanation will be given for an example of forming a third metalfilm (TiAlN film) containing a first metal atom (Ti) and a second metalatom (Al), by alternately repeating the CVD step of supplying the firstsource (TDMAT) containing the first metal atom (Ti) to the substrate andforming on the substrate a first metal film (TiN film) containing thefirst metal atom (Ti) by CVD method; and the ALD step of forming on thesubstrate a second metal film (AlN film) containing the second metalatom (Al) by ALD method, with the step of supplying a second source(TMA) containing the second metal atom (Al) to the substrate and thestep of supplying the reactive gas (NH₃) to the substrate set as onecycle and by performing this cycle for prescribed number of times. Notethat in this specification, the term such as “metal film” means aconductive substance containing metal atoms, and conductive metalnitride film, metal oxide film, metal composite film, and metal alloyfilm, etc, are included therein, other than a film made of metal alone.This will be more specifically described hereinafter.

Substrate Loading Step (S1) and Substrate Placement Step (S2)>

First, the elevation mechanism 207 b is operated, and the support table203 is lowered to the wafer transfer position shown in FIG. 4. Then, thegate valve 251 is opened, so that the processing chamber 201 and thetransfer chamber 271 are communicated with each other. Then, the wafer200, being a processing object, is loaded into the processing chamber201 from the transfer chamber 271 by the transfer robot 273 in a stateof being supported by the transfer arm 273 a (S1). The wafer 200 loadedinto the processing chamber 201 is temporarily placed on the lift pins208 b protruded from the upper surface of the support table 203. Whenthe transfer arm 273 a of the transfer robot 273 is returned to thetransfer chamber 271 from the processing chamber 201, the gate valve 251is closed.

Subsequently, the elevation mechanism 297 b is operated and the supporttable 203 is elevated to the wafer processing position shown in FIG. 3.As a result, the lift pins 208 b are buried from the upper surface ofthe support table 203, and the wafer 200 is placed on the susceptor 217on the upper surface of the support table 203 (S2).

Pressure Adjusting Step (S3) and Temperature Increasing Step (S4)>

Subsequently, the pressure in the processing chamber 201 is controlledto be a prescribed processing pressure, by the pressure adjuster (APC)262 (S3). In addition, electric power supplied to the heater 206 isadjusted, so that a surface temperature of the wafer 200 becomes aprescribed processing temperature (S4). Here, the prescribed processingtemperature and the processing pressure means the processing temperatureand the processing pressure capable of forming the TiN film by CVDmethod in the CVD-TiN step as will be described later, and also theprocessing temperature and the processing pressure capable of formingthe AlN film by ALD method in the ALD-AlN step as will be describedlater. Namely, there are provided the processing temperature and theprocessing pressure such as allowing the first source gas used in theCVD-TiN step to be self-decomposed, and the processing temperature andthe processing pressure such as not allowing the second source gas usedin the ALD-AlN step to be self-decomposed.

In addition, in the substrate loading step (31), the substrate placementstep (32), the pressure adjusting step (S3), and the temperatureincreasing step (S4), by closing the valves va3, vb3, vc2 and openingthe valves vd1, vd2, ve1, ve2, with the vacuum pump 264 operated, N₂ gasis flown through the processing chamber 201 on a constant basis. Thus,adhesion of particles onto the wafer 200 can be suppressed.

In parallel to the steps S1 to S4, the first source is vaporized and thefirst source gas is generated (preliminarily vaporized). Namely, thevalves va1 and va2 are opened and the carrier gas, with flow ratecontrolled by the MFC 222 a, is supplied into the first bubbler 220 a,to thereby vaporize the first source contained in the first bubbler 220a by bubbling and generate the first source gas in advance (preliminaryvaporizing step). In this preliminary vaporizing step, by opening thevalve va4, with the valve va3 closed, while operating the vacuum pump264, the processing chamber 201 is bypassed and exhausted withoutsupplying the first source gas into the processing chamber 201. Aprescribed time is required for stably generating the first source gasby the first bubbler. Therefore, in this embodiment, the first sourcegas is previously generated and by switching the open/close of thevalves va3 and va4, the flow passage of the first source gas isswitched. As a result, by switching the open/close of the valve, speedyand stable start or stop of the first source gas into the processingchamber 201 is possible, and this is preferable.

<CVD-TiN Step (S6)> (First Source Gas Supplying Step)

Subsequently, the valve va4 is closed and the valve va3 is opened, whileoperating the vacuum pump 264, to thereby start the supply of the firstsource gas (Ti source) into the processing chamber 201. The first sourcegas is dispersed by the shower head 240 and is uniformly supplied ontothe wafer 200 in the processing chamber 201. The excess first source gasis flown through the exhaust duct 259, and is exhausted to the exhaustport 260 and the exhaust tube 261 (first source gas supplying step). Atthis time, the processing temperature and the processing pressure areset as the processing temperature and the processing pressure such asallowing the first source gas supplied onto the wafer 200 to beself-decomposed. Therefore, CVD reaction occurs due to thermaldecomposition of the first source gas supplied onto the wafer 200, andthe TiN film is thereby formed on the wafer 200.

In addition, when the first source gas is supplied into the processingchamber 201, preferably the valves vd1 and vd2 stay opened and the N₂gas is always flown through the processing chamber 201, so as to urgedispersion of the first source gas in the processing chamber 201

When a prescribed time is elapsed after the valve va3 is opened andsupply of the first source gas is started, and the TiN film withprescribed film thickness is formed, the valve va3 is closed and thevalve va4 is opened, to thereby stop the supply of the first source gasinto the processing chamber 201. Also, simultaneously the valves va1 andva2 are closed, and the supply of ht carrier gas to the first bubbler220 a is also stopped.

(Purging Step)

After the valve va3 is closed and the supply of the first source gas isstopped, the valves vd1, vd2, ve2, ve2 are opened, to thereby supply theN₂ gas into the processing chamber 201. The N₂ gas is dispersed by theshower head 240 and is supplied into the processing chamber 201, thenflows through the exhaust duct 259, and is exhausted to the exhaust port260 and the exhaust tube 261. Thus, the first source gas and thereactive by-products remained in the processing chamber 201 are removed,and the inside of the processing chamber 201 is purged by N₂ gas(purging step).

In addition, in the CVD-TiN step (S6), the second source is vaporizedand the second source gas is generated (preliminarily vaporized), toprepare for the next ALD-AlN step (S8). Namely, the valves vb1 and vb2are opened and the carrier gas, with flow rate controlled by the MFC 222b, is supplied into the second bubbler 220 b from the second carrier gassupply tube 237 b, to thereby vaporize the second source contained inthe second bubbler 220 b by bubbling and previously generate the secondsource gas (preliminary vaporizing step). In this preliminary vaporizingstep, by opening the valve vb4, with the valve vb3 closed, whileoperating the vacuum pump 264, the processing chamber 201 is bypassedand exhausted without supplying the second source gas into theprocessing chamber 201. Prescribed time is required for stablygenerating the second source gas by the second bubbler. Therefore, inthis embodiment, by previously generating the second source gas andswitching open/close of the valves vb3 and vb4, the flow passage of thesecond source gas is switched. As a result, stable and speedy start orstop of the supply of the second source gas into the processing chamber201 is possible, and this is preferable.

<ALD-AlN Step (S8)> (Second Source Gas Supplying Step)

Subsequently, the valve vb4 is closed and the valve vb3 is opened, whileoperating the vacuum pump 264, and supply of the second source gas (Alsource) into the processing chamber 201 is started. The second sourcegas is dispersed by the shower head 240 and is uniformly supplied ontothe wafer 200 in the processing chamber 201. The excess second sourcegas is flown through the exhaust duct 259, and is exhausted to theexhaust port 260 and the exhaust tube 261 (second source gas supplyingstep). Note that at this time, the processing temperature and theprocessing pressure are set as the processing temperature and theprocessing pressure such as not allowing the second source gas to beself-decomposed. Therefore, the second source gas supplied onto thewafer 200 is adsorbed on the surface of the wafer 200. More accurately,gas molecules of the second source gas are adsorbed on the TiN filmformed on the wafer 200 in the aforementioned CVD-TiN step (S6).

In addition, when the second source gas is supplied into the processingchamber 201, preferably the valves vd1 and vd2 stay opened and the N₂gas is flown through the processing chamber 201 on a constant basis, soas to prevent invasion of the second source gas into the reactive gassupply tube 213 c, and so as to urge the dispersion of the second sourcegas in the processing chamber 201.

When a prescribed time is elapsed after the valve vb3 is opened andsupply of the second source gas is started, the valve vb3 is closed andthe valve vb4 is opened, to thereby stop the supply of the second sourcegas into the processing chamber 201.

(Purging Step)

After the valve vb3 is closed to stop the supply of the second sourcegas, the valves vd1, vd2, ve1, ve2 are opened, to thereby supply the N₂gas into the processing chamber 201. The N₂ gas is dispersed by theshower head 240, and is supplied into the processing chamber 201, thenflows through the exhaust duct 259, and is exhausted to the exhaust port260 and the exhaust tube 261. Thus, the second source gas remained inthe processing chamber 201 is removed and the inside of the processingchamber 201 is purged by the N₂ gas (purging step).

(Reactive Gas Supplying Step)

When purge in the processing chamber 201 is completed, the valves vc1and vc2 are opened, to thereby start the supply of the reactive gas (NH₃gas) into the processing chamber 201. The reactive gas is dispersed bythe shower head 240 and is uniformly supplied onto the wafer 200 in theprocessing chamber 201, reacted with the second source gas adsorbed onthe surface of the wafer 200, to thereby generate the AlN film on thewafer 200. More accurately, the reactive gas reacts with the gasmolecules of the second source gas adsorbed on the TiN film formed onthe wafer 200 in the aforementioned CVD-TiN step (S6), to therebygenerate the AlN film of about less than one atomic layer (less than 1Å) on the TiN film. The excess reactive gas and the by-product are flownthrough the exhaust duct 259, and are exhausted to the exhaust port 260and the exhaust tube 261 (reactive gas supplying step). In addition,when the reactive gas is supplied into the processing chamber 201,preferably the valves ve1 and ve2 stay opened, and the N₂ gas is flownthrough the processing chamber 201 on a constant basis, so as to preventinvasion of the reactive gas into the first source gas supply tube 213 aand the second source gas supply tube 213 b, and so as to urgedispersion of the reactive gas in the processing chamber 201.

When a prescribed time is elapsed after the valves vc1 and vc2 areopened and supply of the reactive gas is started, the valves vc1 and vc2are closed and the supply of the reactive gas into the processingchamber 201 is stopped.

(Purging Step)

After the valves vc1 and vc2 are closed and the supply of the reactivegas is stopped, the valves vd1, vd2, ve1, ve2 are opened and the N₂ gasis supplied into the processing chamber 201. The N₂ gas is dispersed bythe shower head 240 and is supplied into the processing chamber 201,then is flown through the exhaust duct 259, and is exhausted to theexhaust port 260 and the exhaust tube 261. Thus, the reactive gas andthe reaction by-product remained in the processing chamber 201 areremoved, and the inside of the processing chamber 201 is purged by theN₂ gas (purging step).

(Cycle Processing)

By performing the cycle processing of executing the ALD cycle forprescribed number of times (n-cycles), with the aforementioned secondsource gas supplying step, purging step, reactive gas supplying step,and purging step set as one cycle, the AlN film of desired filmthickness is formed on the TiN film formed on the wafer 200 in theaforementioned CVD-TiN step. In addition, after the ALD-AlN step (S8) isended, the valves vb1, vb2 are closed and the supply of the carrier gasto the second bubbler 220 b is stopped.

Note that in the ALD-AlN step (S8), the first source is vaporized andthe first source gas is previously generated (preliminarily vaporized),to prepare for the next CVD-TiN step (S6). Namely, the valves va1 andva2 are opened, and the carrier gas, with flow rate controlled by theMFC 222 a, is supplied into the first bubbler 220 a from the firstcarrier gas supply tube 237 a, to thereby vaporize the first sourcecontained in the first bubbler 220 a by bubbling and preliminarilygenerate the first source gas (preliminary vaporizing step). In thispreliminary vaporizing step, the processing chamber 201 is bypassed andexhausted by opening the valve va4, with the valve va3 closed, whileoperating the vacuum pump 264, without supplying the first source gasinto the processing chamber 201.

<Repeating Step (S10)>

By repeating the aforementioned CVD-TiN step (S6) and the ALD-AlN step(S8) alternately for prescribed number of times (m-times), the titaniumnitride film (CVD-TiN film) by CVD and the aluminium nitride film(ALD-AlN film) by ALD are alternately laminated on the wafer 200, tothereby form titanium aluminum nitride film (TiAlN film), being a metalcomposite film of a desired film thickness.

<Substrate Unloading Step (S11)>

Thereafter, by the reversed procedure to the procedure shown in theaforementioned substrate loading step (S1) and the substrate placementstep (S2), the wafer 200, with the TiAlN film of desired film thicknessformed thereon, is unloaded from the processing chamber 201 into thetransfer chamber 271, and the substrate processing step according tothis embodiment is completed.

Processing conditions of the wafer 200 in the CVD-TiN step (S6)according to this embodiment are given such as:

processing temperature: 250 to 450° C., preferably 350 to 450° C.,processing pressure: 30 to 266 Pa, preferably 30 to 100 Pa, first source(TDMAT) supply flow rate: 10 to 100 sccm, andfilm thickness (TIN): 1 to 5 nm.

Processing conditions of the wafer 200 in the ALD-AlN step (S8)according to this embodiment are given such as:

processing temperature: 250 to 450° C., preferably 350 to 450° C.,processing pressure: 30 to 266 Pa, preferably 30 to 100 Pa, secondsource (TMA) supply flow rate: 10 to 100 sccm, reactive gas (NH₃) supplyflow rate: 50 to 500 sccm, film thickness (AlN): 1 to 5 nm,

Further, 10 to 30 nm are exemplified as a total film thickness formed inthe repeating step (S10), namely, the film thickness of the TiAlN film.

Note that when the processing temperature is set to be less than 250°C., film-forming reaction by CVD is not generated in the CVD-TiN step(S6). Also, when the processing temperature exceeds 450° C., rising of afilm formation rate is explosive, thus making it difficult to controlthe film thickness. Therefore, in the CVD-TiN step (S6), the processingtemperature needs to be set to be 250° C. or more and 450° C. or less,so that the film-forming reaction by CVD is generated, and the filmthickness can be controlled. In addition, when the processingtemperature is set to be 350° C. or more, impurities in the film islessened, thus making resistivity low, and this is preferable.

In addition, in this embodiment, preferably the CVD-TiN step (S6) andthe ALD-AlN step (S8) are performed at the same processing temperatureand/or under the same processing pressure. Namely, in this embodiment,preferably the CVD-TiN step (S6) and the ALD-AlN step (S8) are performedat a constant processing temperature and/or under a constant processingpressure. When the processing temperature and the processing pressureare set to be prescribed values within the aforementioned exemplifiedrange, the film formation by CVD and the film formation by ALD can berealized under the same condition. In this case, a processingtemperature changing step and a processing pressure changing step can beeliminated when the CVD-TiN step (S6) is advanced to the ALD-AlN step(38), and when the ALD-AlN step (S8) is advanced to the CVD-TiN step(S6), thus making it possible to improve throughput.

(3) Advantage According to the Embodiment

According to this embodiment, the first metal film (TiN film), becominga base of the metal composite film (TiAlN film) is formed by CVD method.Therefore, a total film formation rate of the metal composite film canbe more improved than that of a case when the film formation isperformed only by ALD method, thus making it possible to improve thethroughput. In addition, according to this embodiment, when the secondmetal film (AlN film) is formed by ALD method, it is formed, with thefirst metal film (TiN film) as a base, thus urging adsorption of thesource on the baser and the film formation rate can be more improvedthan that of a case when the film formation is performed, with aninsulating film (HfSiON, SiO₂) as a base, and the throughput can beimproved. Note that in a case of being used for a gate electrode, forthe reason described later, it may be preferable that the film formedfirstly and/or lastly is the AlN film.

Further, according to this embodiment, by changing the ALD cycle of thesecond metal film (AlN film) by ALD method, metal composition in themetal composite film (TiAlN film) can be controlled. For example, bychanging the number of ALD cycles of the second metal film (AlN film) byALD method, with the film thickness of the first metal film (TiN film)by CVD method fixed, the composition, namely, the concentration of thesecond metal atoms (Al) in the metal composite film can be controlled.Also, by changing the number of ALD cycles of the second metal film (AlNfilm) by ALD method, a composition profile in a depth direction in themetal composite film can be changed.

Further, according to this embodiment, formation of the first metal film(TiN film) by CVD method and formation of the second metal film (AlNfilm) by ALD method are not simultaneously performed, but performedseparately. Moreover, in the CVD-TiN step (S6), the purging step isperformed after the first source gas supplying step, to thereby surelyperform gas replacement in the processing chamber 201. Further, in theALD-AlN step (S8) also, purging is performed lastly in a cycle process,and the gas in the processing chamber 201 is surely replaced. Thus, thefirst source gas and the second source gas are not mixed with each otherin the processing chamber 201, and it is possible to suppress thegeneration of particles due to vapor phase reaction between the firstsource gas and the second source gas in the processing chamber 201, andimprove uniformity in film thickness and composition of the metalcomposite film (TiAlN film). Note the if the formation of the firstmetal film (TiN film) by CVD method and the formation of the secondmetal film (AlN film) by ALD method are simultaneously performed, mixingtime and reaction of the first source gas and the second source gas needto be considered, thus making it difficult to control the film thicknessand the composition. Further, particles are generated due to vapor phasereaction between the first source gas and the second source gas,resulting in deterioration in the film thickness and the composition ofthe metal composite film (TiAlN film) in some cases, depending on thecombination of gas species.

Also, according to this embodiment, a relatively high temperatureprocess is used in forming the first metal film (TIN film) by CVDmethod. Therefore, an ALD precursor having relatively high decompositiontemperature is selected in forming the second metal film (AlN film).Namely, CVD/ALD is executed at high temperature, and therefore residualimpurities in the film can be lessened by heat, without using a damagesource such as plasma (non-plasma).

Further, according to this embodiment, use amount of the precursor canbe lessened, compared with that of a related art wherein film formationis performed only by ALD method, and therefore it is advantageous interms of cost.

<Other Embodiment of the Present Invention>

The aforementioned embodiment describes an example of vaporizing theliquid source contained inside of the bubbler by bubbling. However, theliquid source may be vaporized by using a vaporizer instead of thebubbler.

Also, the aforementioned embodiment describes an example of using TDMATas Ti source in the CVD-TiN step. However, Ti source such as TiCl₄ mayalso be used, instead of TDMAT. Moreover, the aforementioned embodimentdescribes an example of supplying the Ti source alone to the wafer inthe CVD-TiN step. However, the reactive gas such as NH₃ and H₂ may besimultaneously supplied.

In addition, the aforementioned embodiment describes an example of usingTMA as Al source in the ALD-AlN step. However, the Al source such asAlCl₃ may also be used instead of TMA. In addition, the aforementionedembodiment describes an example of using NH₃ as the reactive gas in theALD-AlN step. However, the gas such as H₂ may also be used instead ofNH₃. In addition, in the ALD-AlN step, the number of ALD cycles may bechanged. By changing the number of ALD cycles, the composition and theconcentration of Al in the metal composite film can be controlled.Moreover, in the ALD-AlN step, the number of ALD cycles may be changedevery time the CVD-TiN step and the ALD-AlN step are repeated. Thus, bychanging the number of ALD cycles, Al composition profile in a depthdirection in the metal composite film can be controlled.

Further, the aforementioned embodiment describes a case of forming theTiAlN film. However, the present invention is not limited thereto, andcan be applied to forming films such as RuAlN, TaAlN, MoAlN, NiAlN,CoAlN.

EXAMPLES Example 1

As an example 1 of the present invention, evaluation of the filmformation rate of the CVD-TiN film formation and the ALD-AlN filmformation will be described. FIG. 6A is a view showing TDMAT supply timedependency of the CVD-TiN film thickness on the HfSiON, AlN, SiO₂ in theCVD-TiN film formation. FIG. 6A shows the TDMAT supply time taken on thehorizontal axis and the TiN film thickness taken on the vertical axis.FIG. 5B is a view showing the ALD cycle number dependency of the ALD-AlNfilm thickness on the HfSiON, TiN, SiO₂ in the ALD-AlN film formation.FIG. 6B shows the number of cycles of ALD-AlN taken on the horizontalaxis, and the AlN film thickness taken on the vertical axis. Note thatthe CVD-TiN film formation and the ALD-AlN film formation in thisevaluation are performed, with the processing conditions set in thevalues within the processing conditions in the aforementionedembodiments.

It is found from FIG. 6A, that almost no change occurs in the filmformation rate on the HfSiON, AlN, and SiO₂, in a case of the CVD-TiNfilm formation. Namely, it is found that the film formation rate hardlydepends on the base film in the CVD-TiN film formation. Meanwhile, it isfound from FIG. 6B, that in a case of the ALD-AlN film formation, thefilm formation rate on TiN is tremendously increased, compared with arelatively low film formation rate on HfSiON and SiO₂, being insulatingfilms. Namely, it is found that the film formation rate in the ALD-AlNfilm formation largely depends on the base film. This is because anadsorption amount of the precursor is changed in an area (ultra-thinfilm area) where the film thickness is extremely thin. It is found fromFIG. 6B, that the film formation rate can be tremendously increased, byperforming ALD-AlN film formation, with TiN set as a base.

In a case of being applied to the gate electrode, AlN is preferably setas the film formed firstly as will be described later (first layer). Inthis case, since the base of the first layer is not TiN, theaforementioned advantage cannot be obtained. However, the ALD-AlN filmformation is performed thereafter, with TiN set as a base, and thereforein this case also, the film formation rate can be tremendouslyincreased.

Example 2

As an example 2 of the present invention, explanation will be given fora film formation evaluation (analysis by sectional TEM photograph) of alaminate film, by repeating the CVD-TiN film formation and the ALD-AlNfilm formation. FIG. 7A shows the sectional TEM photograph afterrepeating the ALD-AlN film formation and the CVD-TiN film formation andforming the laminate film composed of 5-layers (TiAlN of 5-layers),laminate film composed of 11-layers (TiAlN of 11-layers), and laminatefilm composed of 21-layers (TiAlN of 21-layers) respectively. Also, FIG.7B shows the sectional TEM photograph after repeating the ALD-AlN filmformation and the CVD-TiN film formation and forming the laminate filmcomposed of 5-layers (TiAlN of 5-layers), laminate film composed of11-layers (TiAlN of 11-layers), and laminate film composed of 21-layers(TiAlN of 21-layers) respectively, with N₂ annealing applied thereto at900° C. Note that either of the CVD-TiN film formation and the ALD-AlNfilm formation in this evaluation is performed, with the processingconditions set in the values within the range of the processingconditions in the aforementioned embodiment. Further, in each case, theAlN layer is formed firstly and lastly, when the laminated film isformed. Namely, a lowermost layer and an uppermost layer of the laminatelayer are set as the AlN layer. Also, a target film thickness of thelaminate film is set to be about 20 nm to 22 nm.

It is found from FIG. 7A and FIG. 7B, that a boundary between the TiNlayer and the AlN layer is ambiguous, irrespective of presence/absenceof execution of N₂ annealing, in the laminate film composed of 11-layers(TiAlN of 11-layers) and the laminate film composed of 21-layers (TiAlNof 21-layers). In the laminate film composed of 21-layers (TiAlN of21-layers), the boundary between the TiN layer and the AlN layer canhardly be discriminated irrespective of the presence/absence of N2annealing, and it can be said that the laminate film composed of21-layers is visually equivalent to the TiAlN film of one layer. Namely,even when the film of the same thickness is formed, the boundary betweenthe TiN layer and the AlN layer is ambiguous (each layer is mixed withone another), as the number of layers of the laminate film is increased,and this laminate film becomes close to the TiAlN film of one layer. Inaddition, when a case of applying N₂ annealing and a case of notapplying N₂ annealing are compared, it can be confirmed that there isalmost no difference in the laminate film visually, and in each case, nofilm peeling occurs.

Example 3

As an example 3 of the present invention, explanation will be given fora film formation evaluation (profile analysis in XPS depth direction) ofthe laminate film by repeating the CVD-TiN film formation and theALD-AlN film formation. FIG. 8A is a view showing a profile in the XPSdepth direction after the laminate film composed of 11-layers (22 nm)(TiAlN of 11-layers) is formed (TiN:2 nm, AlN:2 nm) and N₂ annealing isapplied thereto at 900° C., and FIG. 8B is a view showing the profile inthe XPS depth direction after the laminate film composed of 21-layers(21 m) (TiAlN of 21-layers) is formed (TiN:1 nm, AlN:1 nm) and annealingis applied thereto at 900° C. Each view shows a sputtering time (same asthe depth direction) taken on the horizontal axis, and the concentrationof each atom in the film taken on the vertical axis. Note that theCVD-TiN film formation and the ALD-AlN film formation in this evaluationwas performed, with the processing conditions set to be the valueswithin the range of the processing conditions in the aforementionedembodiment. In addition, in each case, the AlN layer was firstly andlastly formed, when the laminated film was formed. Namely, the lowermostlayer and the uppermost layer of the laminate film were set as the AlNlayers.

In FIG. 8A and FIG. 8B, it is found from the analysis of the profile inthe XPS depth direction, that carbon (C) concentration in the TiAlN filmis lower than 10 atom % when the laminate film composed of 11-layers(TiAlN of 11-layers) is formed and N₂ annealing is applied thereto at900° C., and is lower than 5 atom % when the laminate film composed of21-layers (TiAlN of 21-layers) is formed and N₂ annealing is appliedthereto at 900° C.

Example 4

As an example 4 of the present invention, explanation will be given fora film formation evaluation (analysis of Al concentration control andresistivity in TiAlN film) of the laminate film by repeating the CVD-TiNfilm formation and the ALD-AlN film formation. FIG. 9A is a view showingALD-AlN cycle number dependency of Al/Ti concentration in the TiAlN filmcomposed of the laminate film of 11-layers. FIG. 9A shows the number ofALD-AlN cycles taken on the horizontal axis, Al concentration taken onthe vertical axis on the left side, and Ti concentration taken on thevertical axis on the right side. FIG. 9B is a view showing Alconcentration dependency of resistivity. FIG. 9B shows the Alconcentration taken on the horizontal axis, and the resistivity taken onthe vertical axis. Note that the CVD-TiN film formation and the ALD-AlNfilm formation in this evaluation were both performed, with theprocessing conditions set to be the values within the processingconditions in the aforementioned embodiment. Further, in each case, theAlN layer was formed firstly and lastly when the laminate film wasformed. Namely, the lowermost layer and the uppermost layer of thelaminate film were set as AlN layers. In addition, the film thickness ofTiN was fixed to 2 nm, and the film thickness of AlN was changed bychanging the number of ALD-AlN cycles.

It is found from FIG. 9A, that the Al concentration in the TiAlN filmcan be controlled to about 35 atom %, by changing the number of ALD-AlNcycles. Also, it is found from FIG. 9B, that the resistivity of theTiAlN film is likely to be increased, as the Al concentration isincreased.

Example 5

As an example 5 of the present invention, the film formation evaluationof the laminate film (TEM/SEM/AFM analysis) by repeating the CVD-TiNfilm formation and the ALD-AlN film formation will be described. FIG.10A shows an SEM photograph after forming the TiAlN film by repeatingthe CVD-TiN film formation and the ALD-AlN film formation, and applyingN₂ annealing thereto at 900° C. FIG. 10B shows a sectional TEMphotograph after forming the TiAlN film by repeating the CVD-TiN filmformation and the ALD-AlN film formation and applying N₂ annealingthereto at 900° C. FIG. 10C shows an AFM photograph after forming theTiAlN film by repeating the CVD-TiN film formation and the ALD-AlN filmformation and applying N₂ annealing thereto at 900° C. In any one ofthese cases, the TiAlN film was constituted by the laminate film of21-layers (21 nm) (TiN:1 nm, AlN:1 nm). In addition, the CVD-TiN filmformation and the ALD-AlN film formation in this evaluation wereperformed, with the processing conditions set in the values within therange of the processing conditions in the aforementioned embodiment.Further, in any one of these cases, when the laminate film was formed,the AlN layer was formed firstly and lastly. Namely, the lowermost layerand the uppermost layer of the laminate film were set as the AlN layers.

It is found from FIG. 10A, FIG. 10B, and FIG. 10C, that no condensationof grains and no peel-off of the film occur. Also, it is found that thesurface of these films is relatively smooth (RMS=1.0 nm).

Example 6

As an example 6 of the present invention, evaluation of pMOS applicationwherein the TiAlN film formed by repeating the CVD-TiN film formationand the ALD-AlN film formation is applied to the gate electrode of pMOS,will be described. FIG. 11A shows an evaluation sample structure, andshows a gate structure of p-MOSFET wherein the TiAlN film formed byrepeating the CVD-TiN film formation and the ALD-AlN film formation isapplied to the gate electrode. Specifically, FIG. 11A shows a structurein which SiON film is formed on a silicon wafer as an interface layer,and HfSiON film is formed thereon as a high dielectric constant gateinsulating film, and TiAlN film and further W film are formed thereon asthe metal gate electrode by the aforementioned method(W/TiAlN/Hf(Al)SiON/SiON/Si wafer). Note that Hf(Al)SiON in the figureshows that Al in the TiAlN film is mixed into the HfSiON film due tothis structure. Also, as the interface layer, SiO₂ film may be usedinstead of the SiON film. FIG. 11B shows the conditions for formingALD-TIAlN, namely, the TiAlN film by repeating the CVD-TiN filmformation and the ALD-AlN film formation, and its laminate structure.FIG. 11C is a view showing Al concentration dependency of the effectivework function in the TiAlN film. FIG. 11C shows the Al concentration inTiAlN taken on the horizontal axis, the effective work function taken onthe vertical axis on the left side, and EOT taken on the vertical axison the right side. Symbol ◯ and symbol □ in the figure show theeffective work function and the EOT, respectively. In addition, in thisevaluation, three kinds of samples, with Al concentration changed like10%, 20%, 30% in the TiAlN film, were prepared. The CVD-TiN filmformation and the ALD-AlN film formation in this evaluation were bothperformed, with the processing conditions in the aforementionedembodiment set in the values within the processing conditions in theaforementioned embodiment. In addition, the TiAlN film is constituted bythe laminate film of 21-layers, and in each case, the AlN layers wereformed firstly and lastly when the laminate film was formed. Namely, theuppermost layer and the lowermost layer of the laminate film were set asthe AlN layers. Further, the effective work function shows data afteractive annealing (Spike) at 1000° C.

It is found from FIG. 11C, that the effective work function is improvedto 4.8 eV by using the TiAlN film (Al concentration: 30%) in thisexample as the metal gate electrode.

Example 7

As an example 7 of the present invention, an evaluation of pMOSapplication wherein the TiAlN film formed by repeating the CVD-TiN filmformation and the ALD-AlN film formation is applied to the gateelectrode of pMOS, will be described. In this evaluation, the effectivework function and the EOT were compared respectively in each case offorming the ALD-AlN film firstly (AlN-first) and a case of forming theCVD-TiN film firstly (TiN-first) on the high dielectric constant gateinsulating film when the TiAlN film was formed.

FIG. 12A and FIG. 13A show an evaluation sample structure, and shows thegate structure of p-MOSFET wherein the TiAlN film formed by repeatingthe CVD-TiN film formation and the ALD-AlN film formation is applied tothe gate electrode. Specifically, FIG. 12A and FIG. 13A show a structurein which SiON film is formed on the silicon wafer as the interfacelayer, and HfSiON film is formed thereon as the high dielectric constantgate insulating film, and TiAlN film and further W film are formedthereon by the aforementioned method as the metal gate electrode(W/TiAlN/HfSiON/SiON/Si WAFER). In addition, the concentration of Hf inthe TiAlN film was set to be 75%. Further, SiO₂ film may also be used asthe interface layer instead of the SiON film.

FIG. 12B and FIG. 13B show the conditions for forming ALD-TiAlNaccording to this example, namely, the TiAlN film by repeating theCVD-TiN film formation and the ALD-AlN film formation, and its laminatestructure. Note that, in the TiAlN film shown in FIG. 12B, the ALD-AlNfilm was formed firstly and the CVD-TiN film and the ALD-AlN film wereformed by alternately laminating 11-layers of them. Namely, theuppermost layer and the lowermost layer of the laminate film wererespectively set as the AlN layers. In addition, the film thickness ofthe uppermost AlN layer was set to be 3 nm. Further, as shown in FIG.13B, in the TiAlN film, the ALD-AlN film was formed firstly and theCVD-TiN film and the ALD-AlN film were alternately formed by laminating21-layers of them. Namely, the lowermost layer and the uppermost layerof the laminate film were respectively set as the AlN layers. Inaddition, the film thickness of the uppermost AlN layer was set to be 3nm.

FIG. 12C and FIG. 13C show the conditions for forming ALD-TiAlNaccording to a comparative example, namely, the TiAlN film by repeatingthe CVD-TiN film formation and the ALD-AlN film formation, and itslaminated structure. Note that in the TiAlN film shown in FIG. 12C, theCVD-TiN film was firstly formed and the CVD-TiN film and the ALD-AlNfilm were formed by alternately laminating 10-layers of them. Namely,the lowermost layer of the laminate film was set as the TiN layer andthe uppermost layer of the laminate film was set as the AlN layer. Inaddition, the film thickness of the uppermost AlN layer was set to be 3nm. Further, in the TiAlN film shown in FIG. 13C, the CVD-TiN film wasfirstly formed, and the CVD-TiN film and the ALD-AlN film were formed byalternately laminating 20-layers of them. Namely, the lowermost layer ofthe laminate film was set as the TiN layer, and the uppermost layer ofthe laminate film was set as the AlN layer. In addition, the filmthickness of the uppermost AlN layer was set to be 3 nm.

FIG. 12D and FIG. 13D are views showing Al concentration dependency ofthe effective work function in the TiAlN film. FIG. 12D and FIG. 13Dshow the Al concentration in TiAlN taken on the horizontal axis, andshow the effective work function taken on the vertical axis on the leftside, and show the EOT taken on the vertical axis on the right side.Mark ◯ and mark □ show the effective work function and EOT when theALD-AlN film is firstly formed, and mark  and mark ▪ show the effectivework function and EOT when the CVD-TiN film is firstly formed,respectively. Note that in this evaluations three kinds of samples, withAl concentration in the TiAlN film changed like 10%, 20%, and 30% wereprepared. Moreover, the CVD-TiN film formation and the ALD-AlN filmformation in this evaluation were performed, with the processingconditions set in the values within the processing conditions in theaforementioned embodiment. Further, the effective work function showsdata after activation annealing (Spike) performed at 1000° C.

As one of the purposes of using the ALD-TiAlN film as the gateelectrode, improvement of the effective work function of the gateelectrode, achieved by efficiently dispersing Al from the TiAlN film asfar as the interface between an interface layer such as the SiON filmand the SiO₂ film, and the High-k film (high dielectric constant film)such as HfSiON film, can be given. It is found from FIG. 12D and FIG.13D, that an improvement width of the effective work function isdifferent depending on whether the ALD-AlN film is firstly formed or theCVD-TiN film is firstly formed. Namely, when the ALD-AlN film is firstlyformed, Al is easily dispersed from the TiAlN film toward a lower layerdirection, and the improvement width of the effective work function isgreat in both samples of 11-layers and 21-layers, and improvement of 0.2eV from 4.6 eV to 4.8 eV can be confirmed. Meanwhile, when the CVD-TiNfilm is firstly formed, Al is hardly dispersed, and it is found that theimprovement width of the effective work function is small in bothsamples of 10-layers and 20-layers. This would be caused by block of thedispersion of Al from the TiAlN film toward the lower layer direction bythe firstly formed TiN film (TiN acts as a dispersion block layer forblocking the dispersion of Al by TiN). Generally, the improvement widthof the effective work function by dispersing Al is about 0.2 eV, and itis found that Al can be efficiently dispersed when the ALD-AlN film isfirstly formed, thus making it easy to exhibit Al doping effect.

Example 8

As an example 8 of the present invention, evaluation of pMOS applicationwherein the TiAlN film formed by repeating the CVD-TiN film formationand the ALD-AlN film formation is applied to the gate electrode of pMOS,will be described. In this evaluation, oxidation resistancecharacteristics of the TiAlN film were compared, between a case that theCVD-TiN film was lastly formed (TiN-last) and a case that the ALD-AlNfilm was lastly formed (AlN-last), when the TiAlN film is formed, namelybetween a case that the uppermost layer was set as the CVD-TiN film anda case that the uppermost layer was set as the ALD-AlN film.

FIG. 14A is a view showing a variation of a degree of oxidation of theTiAlN film with elapse of time, with CVD-TiN film set as the uppermostlayer. FIG. 14A shows an expose time of the TiAlN film to atmosphericair after forming the TiAlN film taken on the horizontal axis, and showselectric resistivity of the TiAlN film taken on the vertical axis. Inaddition, mark ◯ in the figure shows the electric resistivity of theCVD-TiN film. Further, the ALD-AlN film is not formed on the uppermostlayer, and the content of Al in the CVD-TiN film is 0%. Mark □ in thefigure shows the electric resistivity of the TiAlN film, with theuppermost layer set as the CVD-TiN film, which is formed by alternatelyrepeating the CVD-TiN film formation and the ALD-AlN film formation.Note that each ALD-AlN film is formed through ALD cycles of 18-timesrespectively, and the content of Al in the TiAlN film is 30%. Mark A inthe figure shows the electric resistivity of the TiAlN film, with theuppermost layer set as the CVD-TiN film, which is formed by alternatelyrepeating the CVD-TiN film formation and the ALD-AlN film formation. Inaddition, each ALD-AlN film is formed through ALD cycles of 9-times, andthe content of Al in the TiAlN film is 20%. Mark ⋄ in the figure showsthe electric resistivity of the TiAlN film, with the uppermost layer setas the CVD-TiN film, which is formed by alternately repeating the filmformation of CVD-TiN film and the film formation of ALD-AlN. Note thateach ALD-AlN film is formed through four ALD cycles, and the content ofAl in the TiAlN film is 15%.

FIG. 14B is a view showing the variation of the degree of oxidation ofthe TiAlN film with elapse of time, with the uppermost layer set as theALD-AlN film. FIG. 14B shows the expose time of the TiAlN film toatmospheric air after forming the TiAlN film, taken on the horizontalaxis, and shows the electric resistivity of the TiAlN film taken on thevertical axis, respectively. In addition, mark ◯ in the figure shows theelectric resistivity of the TiAlN film formed, with the uppermost layerset as the ALD-AlN film, after forming the CVD-TiN film. Note that theuppermost ALD-AlN film is formed through ALD cycles of 18-times. Mark □in the figure shows the electric resistivity of the TiAlN film, with theuppermost layer set as the ALD-AlN film, which is formed by alternatelyrepeating the CVD-TiN film formation and the ALD-AlN film formation. Inaddition, each ALD-AlN film is formed through ALD cycles of 18-timesrespectively, and the content of Al in the TiAlN film is 30%. Mark Δ inthe figure shows the electric resistivity of the TiAlN film, with theuppermost layer set as the ALD-AlN film, which is formed by alternatelyrepeating the CVD-TiN film formation and the ALD-AlN film formation.Moreover, the uppermost ALD-AlN film is formed through ALD cycles of18-times respectively, and the ALD-AlN film lower than this uppermostALD-AlN film is formed through ALD cycles of 9-times, respectively, andthe content of Al in the TiAlN film is 20%. Mark

in the figure shows the electric resistivity of the TiAlN film, with theuppermost layer set as the ALD-AlN film, which is formed by alternatelyrepeating the CVD-TiN film formation and the ALD-AlN film formation.Note that the uppermost ALD-AlN film is formed through ALD cycles of18-times respectively, and the ALD-AlN film lower than the uppermostALD-AlN film is formed through ALD cycles of 4-times respectively, andthe content of Al in the TiAlN film is 15%.

It is found from FIG. 14A that the electric resistivity is increasedwith elapse of the expose time to atmospheric air, in the TiAlN film,with the uppermost layer set as the CVD-TiN film, thus making it easy tooxidize the TiAlN film. Meanwhile, it is found from FIG. 14B that theelectric resistivity is hardly increased with elapse of the expose timeto atmospheric air in the TiAlN film, with the uppermost layer set asthe ALD-AlN film, thus making it difficult to oxidize the TiAlN film.The reason therefore is considered as follows. The ALD-AlN film formedon the uppermost layer actions as an oxygen block layer for blockingtake-in of the oxygen in the atmospheric air into the CVD-TiN film.Reversely, it is also considered as follows. When the uppermost layer isset as the CVD-TiN film, oxygen in the atmospheric air is easily takeninto the CVD-TiN film, thus making it easy to generate oxidation of theTiAlN film. When a lot of oxygen is contained in the gate electrode,oxygen in the gate electrode passes through the High-k film such asHfSiON in the gate electrode by applying heat treatment thereto at hightemperature, which is then dispersed as far as the interface layer suchas SiON and SiO₂, thus increasing EOT as a result, and scaling of atransistor is sometimes inhibited. However, by setting the uppermostlayer as the ALD-AlN film, such a problem can be solved.

Further Other Embodiment of the Present Invention>

In the aforementioned embodiment, explanation is given for an example ofperforming film formation by using a single wafer processing apparatusfor processing a single substrate at once, as the substrate processingapparatus. However, the present invention is not limited to theaforementioned embodiment. For example, the film formation may beperformed by using a butch-type vertical apparatus for processing aplurality of substrates at once as the substrate processing apparatus.

In addition, the aforementioned embodiment describes an example ofsolving the deterioration of the throughput by improving the filmformation rate by combining CVD method and ALD method. However, if thebutch-type vertical apparatus is used, even in a case of performing filmformation only by ALD method, the deterioration of the throughput can besolved by increasing the number of substrates processed at once. Amethod of performing film formation only by ALD method using thisvertical apparatus, namely, a vertical ALD apparatus, will be described.

FIG. 15 is a schematic block diagram of a vertical processing furnace ofthe vertical ALD apparatus suitably used in this embodiment, whereinFIG. 15A shows a vertical sectional view of a processing furnace 302portion, and FIG. 15B shows a sectional view of the processing furnace302 portion taken along the line A-A of FIG. 15A.

As shown in FIG. 15A, the processing furnace 302 has a heater 307, beinga heating unit (heating mechanism). The heater 307 has a cylindricalshape, and is vertically installed by being supported by a heater base,being a holding plate.

A process tube 303, being a reaction tube, is disposed inside of theheater 307, concentrically with the heater 307. The process tube 303 ismade of a heat resistance material such as quartz (SiO₂) and siliconcarbide (SiC), and is formed into a cylindrical shape, with an upper endclosed and a lower end opened. A processing chamber 301 is formed in acylinder hollow part of the process tube 303, and is constituted so thatwafers 200, being substrates, can be housed in a state of being arrangedin multiple stages in a horizontal posture in a vertical direction by aboat 317 as will be described later.

A manifold 309 is disposed in a lower part of the process tube 303concentrically with the process tube 303. The manifold 309 is made of,for example, stainless, etc, and is formed into a cylindrical shape,with the upper end and the lower end opened. The manifold 309 is engagedwith the process tube 303, and is provided so as to support the processtube 303. In addition, an O-ring 320 a, being a seal member, is providedbetween the manifold 309 and the process tube 303. The process tube 303is set in a state of being installed vertically by being supported bythe heater base. The reaction vessel is formed by the process tube 303and the manifold 309.

A first nozzle 333 a, being a first gas inlet part, and a second nozzle333 b, being a second gas inlet part, are connected to the manifold 309,so as to pass through a side wall of the manifold 309. The first nozzle333 a and the second nozzle 333 b are formed into L-shapes having ahorizontal part and a vertical part respectively, with the horizontalpart connected to the manifold 309, and the vertical part provided in aarc-shaped space between the inner wall of the process tube 303 and thewafer 200, along the inner wall extending from a lower part to an upperpart of the process tube 303, so as to rise toward a laminatingdirection of the wafer 200. First gas supply holes 348 a and second gassupply holes 348 b, being supply holes for supplying gas, arerespectively provided on the side faces of the vertical parts of thefirst nozzle 333 a and the second nozzle 333 b. These first gas supplyholes 348 a and second gas supply holes 348 b are provided further, atthe same opening pitch, having the same opening areas extending from thelower part to the upper part respectively.

A gas supply system connected to the first nozzle 333 a and the secondnozzle 333 b is the same as that of the aforementioned embodiment.However, in this embodiment, a first source gas supply system and asecond source gas supply system are connected to the first nozzle 333 a,and a reactive gas supply system is connected to the second nozzle 333b, and this point is different from the aforementioned embodiment.Namely, in this embodiment, the source gas (first source gas and secondsource gas) and reactive gas are supplied by different nozzles. Inaddition, each source gas may be supplied by different nozzles.

An exhaust tube 331 for exhausting an atmosphere in the processingchamber 301 is provided in the manifold 309. A vacuum pump 346, being avacuum exhaust device, is connected to the exhaust tube 331, through apressure sensor 345, being a pressure detector, and APC (Auto PressureController) valve 342, being a pressure adjuster, and by adjusting theAPC valve 342 based on pressure information detected by the pressuresensor 345, the pressure in the processing chamber 301 can bevacuum-exhausted so as to be set to a prescribed pressure (vacuumdegree). In addition, the APC valve 342 serves as an open/close valvecapable of starting/stopping vacuum-exhaust of the atmosphere in theprocessing chamber 301 by opening/closing the APC valve 342, and furthercapable of adjusting the pressure in the processing chamber 301 byadjusting an opening degree of the valve.

A seal cap 319, being a furnace throat lid member capable of air-tightlyclosing a lower end opening of the manifold 309. The seal cap 319 istouched on the lower end of the manifold 309 from a vertical lower side.The seal cap 319 is made of metal such as stainless, and is formed intoa disc shape. An O-ring 320 b, being a seal member touched on the lowerend of the manifold 309 is provided on an upper surface of the seal cap319. A rotation mechanism 367 for rotating a boat 317 as will bedescribed later, is installed on a face of the seal cap 319 which isopposite side of the processing chamber 301. A rotary shaft 355 of therotation mechanism 367 is passed through the seal cap 319, and isconnected to the boat 317, to thereby rotate the wafer 200 by rotatingthe boat 317. The seal cap 319 is vertically elevated by the boatelevator 315, being an elevating mechanism disposed outside of theprocess tube 303, so that the boat 317 can be loaded and unloadedinto/from the processing chamber 301.

The boat 317, being a substrate holding tool, is made of heat resistancematerial such as quartz and silicon carbide, and is constituted in sucha manner that a plurality of sheets of wafers 200 are arranged, withcenters thereof mutually aligned in a horizontal posture and are held inmultiple stages. In addition, a heat insulating member 318 made of heatresistance materials such as quartz and silicon carbide is provided in alower part of the boat 317, so that heat from the heater 307 is hardlytransmitted to the seal cap 319 side. A temperature sensor 363, being atemperature detector, is installed in the process tube 303, and byadjusting a power supply state to the heater 307 based on temperatureinformation detected by the temperature sensor 363, the temperature inthe processing chamber 301 is set to have a prescribed temperaturedistribution. The temperature sensor 363 is provided along the innerwall of the process tube 303, in the same way as the first nozzle 333 aand the second nozzle 333 b.

A controller 380, being a control part (control unit) controls the APCvalve 342, heater 307, temperature sensor 363, vacuum pump 346, rotationmechanism 367, boat elevator 315, valves va1 to va4, vb1 to vb4, vc1 tovc2, vd1 to vd2, ve1 to ve2, highly durable high speed gas valve V, flowrate controllers 222 a, 222 b, 222 c, 222 d, and 2223.

Next, the substrate processing step of forming a thin film on the wafer200 by ALD method will be described with reference to FIG. 16, as onestep of the manufacturing steps of the semiconductor device, by usingthe processing furnace 302 of the vertical ALD apparatus having theaforementioned structure. Here, by alternately repeating the ALD-AlNstep and the ALD-TiN step, the TiAlN film is formed on the wafer 200 onwhich the HfSiON film is formed on the surface through the SiON film,and at that time, the AlN film is formed firstly (AlN-first) and the AlNfilm is formed lastly (AlN-last). Here, TiCl₄, TMA, and NH₃ are usedrespectively as the first source, the second source, and the reactivegas. In addition, in the description hereinafter, the operation of eachpart constituting the vertical ALD apparatus is controlled by thecontroller 380.

A plurality of wafers 200 are charged into the boat 317 (wafer charge).Then, as shown in FIG. 15A, the boat 317 holding a plurality of sheetsof wafers 200 is elevated by the boat elevator 315 and is loaded intothe processing chamber 301 (boat loading). In this state, the seal cap319 is set in a state of sealing the lower end of the manifold 309through the O-ring 320 b.

The inside of the processing chamber 301 is vacuum-exhausted by thevacuum pump 346, so that the inside of the processing chamber 301 is setto a desired pressure (vacuum degree) At this time, the pressure in theprocessing chamber 301 is measured by the pressure sensor 345, and basedon this measured pressure, the APC valve 342 is feedback-controlled. Inaddition, the inside of the processing chamber is heated by the heater307 so as to be a desired temperature. At this time, the power supplystate to the heater 307 is feedback-controlled based on the temperatureinformation detected by the temperature sensor 363. Subsequently, thewafer 200 is rotated by rotating the boat 317 by the rotation mechanism367.

Thereafter, by alternately repeating the ALD-AlN step and the ALD-TiNstep, the ALD-AlN film and the ALD-TiN film are alternately laminated onthe wafer 200 (HfSiON film), to thereby form the TiAlN film. At thattime, by performing the ALD-AlN step firstly, the ALD-AlN film is formedfirstly (AlN-first). Further, by performing the ALD-AlN step lastly, theALD-AlN film is formed lastly (AlN-last). Namely, both of the lowermostlayer and the uppermost layer of the TiAlN film are set as the ALD-AlNfilm.

In addition, the procedure of the ALD-AlN step is the same as theALD-AlN step (S8) in the aforementioned embodiment. Meanwhile, theprocedure of the ALD-TiN step (S6) is different from the CVD-TiN step inthe aforementioned embodiment. The ALD-TiN step will be describedhereinafter.

(First Source Gas Supplying Step)

In the ALD-TiN step, the valve va4 is closed and the valve va3 isopened, with the vacuum pump 346 operated, and supply of the firstsource gas (Ti source) into the processing chamber 301 is started. Thefirst source gas is uniformly supplied onto the wafer 200 in theprocessing chamber 301 through the first nozzle 333 a. The excess firstsource gas is exhausted to the exhaust tube 331 (first source gassupplying step). At this time, the processing temperature and theprocessing pressure are set to be the processing temperature and theprocessing pressure not allowing the first source gas to beself-decomposed. Therefore, gas molecules of the first source gas areadsorbed on the AlN film formed on the wafer 200 in the ALD-AlN step.When prescribed time is elapsed after supply of the first source gas isstarted by opening the valve va3, the valve va3 is closed and the valveva4 is opened, to thereby stop the supply of the first source gas intothe processing chamber 301. Also, simultaneously, the valve va1 and thevalve va2 are closed, to thereby stop the supply of the carrier gas tothe first bubbler 220 a.

(Purging Step)

After the valve va3 is closed and the supply of the first source gas isstopped, the valves vd1, vd2, ve1, and ve2 are opened, to thereby supplyN₂ gas into the processing chamber 301. The N₂ gas is supplied into theprocessing chamber 301 through the first nozzle 333 a and the secondnozzle 333 b, and is exhausted to the exhaust tube 331. Thus, the firstsource gas remained in the processing chamber 301 is removed, and theinside of the processing chamber 301 is purged by N₂ gas.

(Reactive Gas Supplying Step)

When purging inside of the processing chamber 301 is completed, thevalves vc1 and vc2 are opened, and supply of the reactive gas (NH₃ gas)into the processing chamber 301 is started. The reactive gas isuniformly supplied onto the wafer 200 in the processing chamber 301through the second nozzle 333 b, and is reacted with the gas moleculesof the first source gas adsorbed on the AlN film formed on the wafer 200in the ALD-AlN step, to thereby generate the TiN film of about less thanone atomic layer (less than 1 Å) on the AlN film. The excess reactivegas and the reaction by-product are exhausted to the exhaust tube 331(reactive gas supplying step). When prescribed time is elapsed aftersupply of the reactive gas is started by opening the valves vc1 and vc2,the valves vc1 and vc2 are closed, to thereby stop the supply of thereactive gas into the processing chamber 301.

(Purging Step)

After supply of the reactive gas is stopped by closing the valves vc1and vc2, the valves vd1, vd2, ve1, and ve2 are opened, to thereby supplyN₂ gas into the processing chamber 301. The N₂ gas is supplied into theprocessing chamber 301 through the first nozzle 333 a and the secondnozzle 333 b, and is exhausted to the exhaust tube 331. Thus, thereactive gas and the reaction by-product remained in the processingchamber 301 are removed, and the inside of the processing chamber 301 ispurged by N₂ gas.

(Cycle Processing)

By performing cycle processing of executing prescribed number of timesof ALD cycles, with the aforementioned first source gas supplying step,purging step, reactive gas supplying step, and purging step, set as onecycle, the TiN film of a desired film thickness, is formed on the TiNfilm formed on the wafer 200 in the ALD-AlN step.

After the TiAlN film of a prescribed film thickness is formed on thewafer 200 (HfSiON film) by alternately repeating the ALD-AlN step andthe ALD-TiN step for prescribed number of times, the seal cap 319 islowered by the boat elevator 315, and the lower end of the manifold 309is opened and the wafer, with TiAlN film of a prescribed film thicknessformed thereon, is unloaded to outside of the process tube 303 from thelower end of the manifold 309 in a state of being held by the boat 317(boat unloading). Thereafter, the already processed wafer 200 is takenout from the boat 317 (wafer discharge).

According to an example given by this embodiment, by alternatelyrepeating the ALD-AlN step and the ALD-TiN step, the TiAlN film isformed on the wafer 200 by using the vertical ALD apparatus, and at thattime, the AlN film is formed firstly and lastly. However, the presentinvention is not limited thereto. For example, by alternately repeatingthe ALD-AlN step and the CVD-TiN step, the TiAlN film is formed on thewafer 200 by using the vertical ALD apparatus, and at that time, the AlNfilm may be formed firstly and lastly. In this case, the film-formingrate can be improved and throughput can be further improved more than acase that film formation is performed only by ALD method.

<Preferred Aspects of the Present Invention>

Preferred aspects of the present invention will be additionallydescribed hereinafter.

According to one of the aspects of the present invention, there isprovided a manufacturing method of a semiconductor device, including thesteps of:

forming an insulating film on a substrate;

forming a high dielectric constant insulating film on the insulatingfilm; and

forming a titanium aluminum nitride film on the high dielectric constantinsulating film,

wherein in the step of forming the titanium aluminum nitride film,formation of an aluminium nitride film and formation of a titaniumnitride film are alternately repeated, and at that time, the aluminiumnitride film is formed firstly and/or lastly.

Preferably, the aluminium nitride film is formed by ALD method, and thetitanium nitride film is formed by ALD method or CVD method, and theformation of the aluminium nitride film and the formation of thetitanium nitride film are performed in the same processing chamber, withthe temperature of the substrate set to be the same temperature.

Also preferably, the aluminium nitride film is formed by setting thestep of supplying a source containing aluminium atoms and the step ofsupplying gas containing nitrogen atoms as one cycle, and repeating thiscycle multiple number of times, and by changing the number of times ofthe cycle, concentration of the aluminium atoms in the titanium aluminumnitride film is controlled.

Also preferably, the insulating film is a silicon oxide film or asilicon oxynitride film, and the high dielectric constant insulatingfilm is a hafnium silicate nitride film.

According to another aspect of the present invention, there is provideda manufacturing method of a semiconductor device, including the stepsof:

forming an insulating film on a substrate;

forming a high dielectric constant insulating film on the insulatingfilm; and

forming a titanium aluminum nitride film on the high dielectric constantinsulating film,

wherein in the step of forming the titanium aluminum nitride film,formation of an aluminium nitride film by ALD method and formation of atitanium nitride film by CVD method are alternately repeated in the sameprocessing chamber, with purging of an inside of the processing chamberinserted therebetween, in a state of setting temperature of thesubstrate to the same temperature, and at that time, the aluminiumnitride film is formed firstly and/or lastly.

Preferably, the formation of the aluminium nitride film and theformation of the titanium nitride film are performed in a state ofsetting a pressure in the processing chamber to the same pressure.

Also preferably, the aluminium nitride film is formed by setting thestep of supplying a source containing aluminium atoms and the step ofsupplying gas containing nitrogen atoms as one cycle, and repeating thiscycle multiple number of times, and by changing the number of times ofthe cycle, concentration of the aluminium atoms in the titanium aluminumnitride film is controlled.

Also preferably, the insulating film is a silicon oxide film or asilicon oxynitride film, and the high dielectric constant insulatingfilm is a hafnium silicate nitride film.

According to further another aspect of the present invention, there isprovided a substrate processing apparatus, including:

a processing chamber that processes a substrate on which a highdielectric constant insulating film is formed on a surface through aninsulating film;

a first source supply system that supplies a first source containingaluminium atoms into the processing chamber;

a second source supply system that supplies a second source containingtitanium atoms into the processing chamber;

a reactive gas supply system that supplies reactive gas containingnitrogen atoms into the processing chamber;

a heater that heats the substrate in the processing chamber; and

a controller that controls the first source supply system, the secondsource supply system, the reactive gas supply system, and the heater, soas to form a titanium aluminum nitride film on the high dielectricconstant insulating film formed on the substrate by alternately andrepeatedly performing formation of an aluminium nitride film bysupplying the first source and the reactive gas into the processingchamber, and formation of a titanium nitride film by supplying thesecond source and the reactive gas into the processing chamber, and atthat time, so as to form the aluminium nitride film firstly and/orlastly.

According to further another aspect of the present invention, there isprovided a semiconductor device, including:

an insulating film formed on a substrate;

a high dielectric constant insulating film formed on the insulatingfilm; and

a titanium aluminum nitride film formed on the high dielectric constantinsulating film,

wherein the titanium aluminum nitride film is composed of a laminatedfilm of an aluminium nitride film and a titanium nitride film, and alowermost layer and/or an uppermost layer of the titanium aluminumnitride film is the aluminium nitride film.

According to an aspect of the present invention, there is provided amanufacturing method of a semiconductor device, including the steps of:

forming a third metal film containing first metal atoms and second metalatoms, by alternately repeating the step of forming on a substrate afirst metal film containing the first metal atoms by CVD method, and thestep of forming on the substrate a second metal film containing thesecond metal atoms by ALD method.

Preferably, the step of forming the first metal film and the step offorming the second metal film are continuously performed in the sameprocessing chamber.

Also preferably, the step of forming the first metal film and the stepof forming the second metal film are performed at the same processingtemperature and/or under the same processing pressure.

Also preferably, in the step of forming the first metal film, a firstsource containing the first metal atoms is supplied to a substrate, andin the step of forming the second metal film, the step of supplying asecond source containing the second metal atoms to the substrate and thestep of supplying reactive gas to the substrate are set as one cycle,and this cycle is repeated multiple number of times.

Also preferably, by changing the number of the cycles in the step offorming the second metal film, concentration of the second metal atomsin the third metal film is controlled.

Also preferably, the first metal atoms are titanium atoms (Ti), and thesecond metal atoms are aluminium atoms (Al).

Also preferably, the first metal film is a titanium nitride film (TiNfilm), the second metal film is an aluminium nitride film (AlN film),and the third metal film is an aluminum titanium nitride film (TiAlNfilm).

According to another aspect of the present invention, there is provideda substrate processing apparatus, including:

a processing chamber that processes a substrate;

a first source supply system that supplies a first source containingfirst metal atoms into the processing chamber;

a second source supply system that supplies a second source containingsecond metal atoms into the processing chamber;

a reactive gas supply system that supplies reactive gas into theprocessing chamber;

a heater that heats the substrate in the processing chamber; and

a controller that controls the first source supply system, the secondsource supply system, the reactive gas supply system, and the heater, sothat a first metal film containing the first metal atoms is formed onthe substrate by a CVD method by supplying the first source into theprocessing chamber, then a second metal film containing the second metalatoms is formed on the substrate by an ALD method by supplying thesecond source and the reactive gas alternately into the processingchamber, and a third metal film containing the first metal atoms and thesecond metal atoms is formed by alternately repeating the aforementionedCVD method and the ALD method.

1. A manufacturing method of a semiconductor device, comprising thesteps of: forming an insulating film on a substrate; forming a highdielectric constant insulating film on the insulating film; and forminga titanium aluminum nitride film on the high dielectric constantinsulating film, wherein in the step of forming the titanium aluminumnitride film, formation of an aluminium nitride film and formation of atitanium nitride film are alternately repeated, and at that time, thealuminium nitride film is formed firstly and/or lastly.
 2. Themanufacturing method of the semiconductor device according to claim 1,wherein the aluminium nitride film is formed by ALD method, and thetitanium nitride film is formed by ALD method or CVD method, and theformation of the aluminium nitride film and the formation of thetitanium nitride film are performed in the same processing chamber, withthe temperature of the substrate set to be the same temperature.
 3. Themanufacturing method of the semiconductor device according to claim 1,wherein the aluminium nitride film is formed by setting the step ofsupplying a source containing aluminium atoms and the step of supplyinggas containing nitrogen atoms as one cycle, and repeating this cyclemultiple number of times, and by changing the number of times of thecycle, concentration of the aluminium atoms in the titanium aluminumnitride film is controlled.
 4. The manufacturing method of thesemiconductor device according to claim 1, wherein the insulating filmis a silicon oxide film or a silicon oxynitride film, and the highdielectric constant insulating film is a hafnium silicate nitride film.5. A manufacturing method of a semiconductor device, comprising thesteps of: forming an insulating film on a substrate; forming a highdielectric constant insulating film on the insulating film; and forminga titanium aluminum nitride film on the high dielectric constantinsulating film, wherein in the step of forming the titanium aluminumnitride film, formation of an aluminium nitride film by ALD method andformation of a titanium nitride film by CVD method are alternatelyrepeated in the same processing chamber, with purging an inside of theprocessing chamber inserted therebetween, in a state of settingtemperature of the substrate to the same temperature, and at that time,the aluminium nitride film is formed firstly and/or lastly.
 6. Themanufacturing method of the semiconductor device according to claim 5,wherein the formation of the aluminium nitride film and the formation ofthe titanium nitride film are performed in a state of setting a pressurein the processing chamber to the same pressure.
 7. The manufacturingmethod of the semiconductor device according to claim 5, wherein thealuminium nitride film is formed by setting the step of supplying asource containing aluminium atoms and the step of supplying gascontaining nitrogen atoms as one cycle, and repeating this cyclemultiple number of times, and by changing the number of times of thecycle, concentration of the aluminium atoms in the titanium aluminumnitride film is controlled.
 8. The manufacturing method of thesemiconductor device according to claim 5, wherein the insulating filmis a silicon oxide film or a silicon oxynitride film, and the highdielectric constant insulating film is a hafnium silicate nitride film.9. A substrate processing apparatus, comprising: a processing chamberthat processes a substrate on which a high dielectric constantinsulating film is formed on a surface through an insulating film; afirst source supply system that supplies a first source containingaluminium atoms into the processing chamber; a second source supplysystem that supplies a second source containing titanium atoms into theprocessing chamber; a reactive gas supply system that supplies reactivegas containing nitrogen atoms into the processing chamber; a heater thatheats the substrate in the processing chamber; and a controller thatcontrols the first source supply system, the second source supplysystem, the reactive gas supply system, and the heater, so as to form atitanium aluminum nitride film on the high dielectric constantinsulating film formed on the substrate by alternately and repeatedlyperforming formation of an aluminium nitride film by supplying the firstsource and the reactive gas into the processing chamber, and formationof a titanium nitride film by supplying the second source and thereactive gas into the processing chamber, and at that time, so as toform the aluminium nitride film firstly and/or lastly.